Bug fix for GPIO under recent Linux kernel versions

Makefile

@@ -77,7 +77,7 @@ $(ARDUINO): $(ARDUINO_LIB_OBJS)
 
 # Gateway Build
 $(GATEWAY): $(GATEWAY_OBJECTS) $(ARDUINO_LIB_OBJS)
-	$(CXX) $(LDFLAGS) -o $@ $(GATEWAY_OBJECTS) $(ARDUINO_LIB_OBJS)
+	$(CXX) $(LDFLAGS) -o $@ $(GATEWAY_OBJECTS) $(ARDUINO_LIB_OBJS) $(LATE_LDFLAGS)
 
 # Include all .d files
 -include $(DEPS)

configure

@@ -318,7 +318,7 @@ signing=none
 signing_request_signatures=false
 encryption=false
 
-params="SOC CFLAGS CXXFLAGS CPPFLAGS LDFLAGS PREFIX CC CXX ARDUINO_LIB_DIR BUILDDIR BINDIR GATEWAY_DIR INIT_SYSTEM SPI_DRIVER TYPE"
+params="SOC CFLAGS CXXFLAGS CPPFLAGS LDFLAGS LATE_LDFLAGS PREFIX CC CXX ARDUINO_LIB_DIR BUILDDIR BINDIR GATEWAY_DIR INIT_SYSTEM SPI_DRIVER TYPE"
 
 for opt do
     if [ "$opt" = "-h" ] || [ "$opt" = "--help" ]; then
@@ -707,6 +707,7 @@ fi
 
 LDFLAGS="-pthread $LDFLAGS"
 CPPFLAGS="$CPUFLAGS $CPPFLAGS"
+LATE_LDFLAGS="-Wl,-Bstatic -lgpiod -Wl,-Bdynamic"
 
 printf "  ${OK} CPPFLAGS: $CPPFLAGS\n"
 printf "  ${OK} CXXFLAGS: $CXXFLAGS\n"

hal/architecture/Linux/drivers/core/interrupt.cpp

@@ -37,6 +37,7 @@
 struct ThreadArgs {
 	void (*func)();
 	int gpioPin;
+	struct gpiod_line *line;
 };
 
 volatile bool interruptsEnabled = true;
@@ -87,10 +88,10 @@ int piHiPri(const int pri)
 void *interruptHandler(void *args)
 {
 	int fd;
-	struct pollfd polls;
 	char c;
 	struct ThreadArgs *arguments = (struct ThreadArgs *)args;
 	int gpioPin = arguments->gpioPin;
+	struct gpiod_line *line = arguments->line;
 	void (*func)() = arguments->func;
 	delete arguments;
 
@@ -101,28 +102,26 @@ void *interruptHandler(void *args)
 		return NULL;
 	}
 
-	// Setup poll structure
-	polls.fd     = fd;
-	polls.events = POLLPRI | POLLERR;
-
 	while (1) {
 		// Wait for it ...
-		int ret = poll(&polls, 1, -1);
+		// New version
+		int ret = gpiod_line_event_wait(line, NULL);
 		if (ret < 0) {
 			logError("Error waiting for interrupt: %s\n", strerror(errno));
 			break;
 		}
-		// Do a dummy read to clear the interrupt
-		//	A one character read appars to be enough.
-		if (lseek (fd, 0, SEEK_SET) < 0) {
-			logError("Interrupt handler error: %s\n", strerror(errno));
-			break;
-		}
-		if (read (fd, &c, 1) < 0) {
-			logError("Interrupt handler error: %s\n", strerror(errno));
-			break;
+		struct gpiod_line_event event;
+		if (gpiod_line_event_read(line, &event) == 0) {
+			if (event.event_type == GPIOD_LINE_EVENT_RISING_EDGE) {
+				logInfo("RISING Edge\n");
+			} else {
+				logInfo("FALLING Edge\n");
+			}
 		}
+
 		// Call user function.
+		logError("Calling user function\n");
+
 		pthread_mutex_lock(&intMutex);
 		if (interruptsEnabled) {
 			pthread_mutex_unlock(&intMutex);
@@ -131,6 +130,8 @@ void *interruptHandler(void *args)
 			pthread_mutex_unlock(&intMutex);
 		}
 	}
+	// Adding gpiod closing instructions
+	gpiod_line_release(line);
 
 	close(fd);
 
@@ -153,72 +154,53 @@ void attachInterrupt(uint8_t gpioPin, void (*func)(), uint8_t mode)
 		usleep(1000);
 	}
 
-	// Export pin for interrupt
-	if ((fd = fopen("/sys/class/gpio/export", "w")) == NULL) {
-		logError("attachInterrupt: Unable to export pin %d for interrupt: %s\n", gpioPin, strerror(errno));
-		exit(1);
-	}
-	fprintf(fd, "%d\n", gpioPin);
-	fclose(fd);
+	char *chipname = "gpiochip0";
+	unsigned int line_num = gpioPin;
+	struct gpiod_line_event event;
+	struct gpiod_chip *chip;
+	struct gpiod_line *line;
 
-	// Wait a bit the system to create /sys/class/gpio/gpio<GPIO number>
-	usleep(1000);
 
-	snprintf(fName, sizeof(fName), "/sys/class/gpio/gpio%d/direction", gpioPin) ;
-	if ((fd = fopen (fName, "w")) == NULL) {
-		logError("attachInterrupt: Unable to open GPIO direction interface for pin %d: %s\n",
-		         gpioPin, strerror(errno));
-		exit(1) ;
+	chip = gpiod_chip_open_by_name(chipname);
+	if (!chip) {
+		logError("Open chip failed\n");
+		exit(1);
 	}
-	fprintf(fd, "in\n") ;
-	fclose(fd) ;
 
-	snprintf(fName, sizeof(fName), "/sys/class/gpio/gpio%d/edge", gpioPin) ;
-	if ((fd = fopen(fName, "w")) == NULL) {
-		logError("attachInterrupt: Unable to open GPIO edge interface for pin %d: %s\n", gpioPin,
-		         strerror(errno));
-		exit(1) ;
+	line = gpiod_chip_get_line(chip, line_num);
+	if (!line) {
+		logError("Get line failed\n");
+		exit(1);
 	}
 
 	switch (mode) {
 	case CHANGE:
-		fprintf(fd, "both\n");
+		gpiod_line_request_both_edges_events(line, "gpiointerrupt");
 		break;
 	case FALLING:
-		fprintf(fd, "falling\n");
+		gpiod_line_request_falling_edge_events(line, "gpiointerrupt");
 		break;
 	case RISING:
-		fprintf(fd, "rising\n");
+		gpiod_line_request_rising_edge_events(line, "gpiointerrupt");
 		break;
 	case NONE:
-		fprintf(fd, "none\n");
 		break;
 	default:
 		logError("attachInterrupt: Invalid mode\n");
-		fclose(fd);
 		return;
 	}
-	fclose(fd);
 
 	if (sysFds[gpioPin] == -1) {
-		snprintf(fName, sizeof(fName), "/sys/class/gpio/gpio%d/value", gpioPin);
-		if ((sysFds[gpioPin] = open(fName, O_RDONLY)) < 0) {
+		if ((sysFds[gpioPin] = gpiod_line_event_get_fd(line)) < 0) {
 			logError("Error reading pin %d: %s\n", gpioPin, strerror(errno));
 			exit(1);
 		}
 	}
 
-	// Clear any initial pending interrupt
-	ioctl(sysFds[gpioPin], FIONREAD, &count);
-	for (int i = 0; i < count; ++i) {
-		if (read(sysFds[gpioPin], &c, 1) == -1) {
-			logError("attachInterrupt: failed to read pin status: %s\n", strerror(errno));
-		}
-	}
-
 	struct ThreadArgs *threadArgs = new struct ThreadArgs;
 	threadArgs->func = func;
 	threadArgs->gpioPin = gpioPin;
+	threadArgs->line = line;
 
 	// Create a thread passing the pin and function
 	pthread_create(threadIds[gpioPin], NULL, interruptHandler, (void *)threadArgs);
@@ -238,14 +220,6 @@ void detachInterrupt(uint8_t gpioPin)
 		close(sysFds[gpioPin]);
 		sysFds[gpioPin] = -1;
 	}
-
-	FILE *fp = fopen("/sys/class/gpio/unexport", "w");
-	if (fp == NULL) {
-		logError("Unable to unexport pin %d for interrupt\n", gpioPin);
-		exit(1);
-	}
-	fprintf(fp, "%d", gpioPin);
-	fclose(fp);
 }
 
 void interrupts()

hal/architecture/Linux/drivers/core/interrupt.h

@@ -24,6 +24,8 @@
 
 #include <stdint.h>
 
+#include <gpiod.h>
+
 #define CHANGE 1
 #define FALLING 2
 #define RISING 3